The global type 2 diabetes (T2D) epidemic cannot be explained by genetics alone. Environmental factors, including rapid urbanisation and lifestyle habits, have also contributed to this disease through their ability to modulate the establishment and maintenance of epigenetic modifications such as DNA methylation.

Pinzón-Cortés et al. have investigated a lesser known epigenetic change – DNA hydroxymethylation, an intermediary step in DNA demethylation – in peripheral blood DNA of patients with T2D who had good or poor glycaemic control compared with controls.

The levels of both DNA methylation and hydroxymethylation in peripheral blood were increased in T2D patients compared with controls. Interestingly, upon more detailed analysis, this difference was not found to be present between well-controlled patients and controls. This suggests a direct relationship between chronic hyperglycaemia and cumulative changes in the epigenome. Furthermore, the expression of key genes involved in mediating these epigenetic changes was also altered in patients with poorly controlled T2D.

These findings highlight the importance of maintaining adequate glycaemic control in T2D patients, not only to prevent the development of diabetic complications but also to ensure longer term epigenomic health.

Read the full article in Endocrine Connections 6 708–725